You’ll also need about two gigabytes of space free while the game installs, but you’re free to fill that gap back up again when the game’s ready to play.

Giant file sizes aside, Riven is a first-person puzzle game that has you hot footing it around a mysterious island. You’ll be picking up objects, pulling levers, and solving obtuse head scratchers as you contend with the power-hungry ruler Gehn.

The app features achievements in Game Center, multitasking, and auto-save, as well as a bookmark system for manually marking down your progress. You also have the ability to zoom in to see more detail, and new hot-spot hints not available in the original PC release.

If you have the space, and the patience, you can download the monster game Riven now on iPhone and iPod touch for £3.49 / $5.99 / €4.99.